A virulent white supremacist who tried to turn a sleepy North Dakota town into a neo-Nazi community has discovered, on live television, that he is part black.

Craig Cobb might have to throw himself out of town if the racist American maintains his hatred of blacks after a DNA test that showed he was of 14 per cent Sub-Saharan African heritage, according to a clip from the Trisha Goddard Show.

The results were revealed during taping of an episode scheduled to air on Nov. 18, but the clip has appeared in a MailOnline video — showing Cobb looking unimpressed as the audience bursts into laughter.

"Sweetheart, you have a little black in you," Goddard says as Cobb insists the results are "statistical noise." He rejects her when she tries to fist-pump him and call him "bro."

Cobb later told the Bismarck Tribune he doesn't believe the results and he's planning to take other tests in an attempt to prove he's all white.

While DNA tests to determine ancestry are sometimes considered of dubious accuracy, there's no testing required to know that Cobb's views are poisonous.

He's wanted in Canada for promoting hatred, and the small town of Leith, North Dakota is taking whatever action it can against the 61-year-old after he bought more than a dozen lots there to sell to other white supremacists.

Leith's population is primarily Caucasian, but one of its black residents speaking to the Bismarck Tribune, Bobby Harper, said he found the results hysterical.